Premature failing of the 7533 DAC's on the sound boards. During extensive research on the sound boards Digital to Analog converter circuit, we have discovered a transient condition which may result in premature failure of this part.
Cause: The condition is dus to overstressed metalization related to pin 1 on this chip. The situation occurs on power-down when the Vcc begins to fall and reaches about 1.5 volts. At this time, the voltage on pin 1 exceeds Vcc for a fraction of a second. The DAC is not designed to withstand this condition.
Cure: Remove the 47uf capacitor connected to pin 1 of this chip. This will eliminate the transient condition on the circuit, and testing indicates that this removal has no negative effect on the overall operation of the circuit.
Board names: Remove Capacitor
1-Sounds Good C122
2-Cheap Squeak Deluxe C122
3-Artificial Artist C122
4-Turbo Cheap Squeak C12
5-T.C.S. Pinball C30
6-Sounds Deluxe Pinball C12
Pinballs List
Black Belt #5
City Slicker #5
Dungeons and Dragons #6
Escape from the Lost World #6
Hardbody #5
Heavy Metal #6
Motordome #5
Party Animal #6
Special Force #6
Strange Science #5
Video Games List
Demo Derby #4
Max RPM #4
Power Drive #1
Rampage #1
Sarge #4
Spy Hunter #2
Spy Hunter 2 #1 +#4
Star Guards #1
Xenophobe #1
Zwackery #3
